"Fee simple subject to condition subsequent" is a legal term that refers to a type of ownership interest in a property. It means that the owner has full and complete ownership of the property, but that ownership is subject to certain conditions or requirements. These conditions usually dictate how the property can be used or maintained, and if they are violated, ownership of the property may revert back to the original owner or to another designated entity. Synonyms for this term include "conditional fee," "fee conditional," and "defeasible fee." These terms all describe a type of ownership interest that is subject to conditions or requirements that must be met in order to maintain ownership.